Giant rock ‘Onion Bags’ to protect Cosy Corner seawall

Published on 08 March 2023

Giant rock ‘Onion-Bags’ to protect Cosy Corner seawall

The Great Ocean Road Coast and Parks Authority will be installing rock bags along the Cosy Corner timber seawall in Torquay in coming weeks to provide short-term protection of the aging infrastructure.

The bags, each weighing around four tonnes and resembling a giant onion bag, will be installed along the entire length of the 160-metre wall, which extends from the Cosy Corner toilet block to Pt Danger.

The seawall, built more than half a century ago, protects the Pt Danger headland and Cosy Corner picnic area – two of the Great Ocean Road’s most popular and visited locations – from coastal erosion. The seawall is adjacent to the Pt Danger Marine Sanctuary, which is managed by Parks Victoria and has high environmental values.

A significant erosion event in March last year removed a large volume of sand from the front of the seawall, exposing the structure to wave attack which caused several sections of the seawall to collapse. Immediate repairs were completed in June last year to prevent further damage and protect public safety.

The works, which are funded by the Department of Energy, Environment and Climate Action and have received Marine and Coast Act consent, will involve craning the rock bags into place over two to three weeks, pending weather conditions, during low tide periods.

The rocks and the bags have been tested to ensure they will not impact the marine environment, and the Authority and Parks Victoria have worked closely with the project contractor on an environmental management plan for the works.

The Authority has engaged the Wadawurrung Traditional Owners Aboriginal Corporation to ensure the protection of any Aboriginal heritage in the area. WTOAC representatives will be on site during the works to provide supervision.

The rock bags will provide temporary protection to the wall while adaptation planning and community consultation occurs. The long-term plan is to undertake a technical investigation of coastal processes and hazards, supported by comprehensive community engagement, which will inform the design for a replacement coastal protective structure.

Quotes attributable to Great Ocean Road Coast and Parks Authority CEO Jodie Sizer  

“Coastal erosion is one of the biggest threats facing our coastline, and it is only getting greater in the face of climate change.  

“These works will provide temporary protection while work on a longer-term plan to protect this hugely popular and much-loved coastal location.”